As is well known, there is no means of ventilation in a submarine, spacecraft, or the like. Therefore, a carbon dioxide separation apparatus for keeping a carbon dioxide concentration to a certain level or lower is used in a crew cabin of a submarine or a spacecraft. Meanwhile, in an air-conditioned office or the like, ventilation is necessary. In recent years, the atmospheric carbon dioxide concentration has been increasing. Accordingly, a necessary amount of ventilation for keeping a carbon dioxide concentration in an office to a certain value or less has been increasing every year. In accordance with such an increase in necessary ventilation amount, energy loss in air-conditioning such as cooling or heating has been increasing. In view of this situation, it has been considered to suppress the ventilation amount with use of a carbon dioxide separating air-conditioning system, thereby reducing such energy loss in air conditioning.
Reduction of emission of carbon dioxide known as a greenhouse gas is a global issue. In this respect, development has been conducted on solar energy, wind energy, geothermal energy, etc. At the same time, development and verification tests have been internationally conducted on technology for separating and collecting carbon dioxide contained in a flue gas that is emitted due to use of a fossil fuel such as coal, and storing the collected carbon dioxide under the soil, for example.
Chemical absorption is currently under consideration as one of techniques for large-scale carbon dioxide separation and collection intended for flue gas treatment. The chemical absorption technique is used for separating and collecting carbon dioxide from a flue gas emitted from an ironworks blast furnace or the like. Also, development on a new absorbing liquid has been conducted (see Patent Literature 1). Meanwhile, in the field of carbon dioxide adsorption and separation technology, it is known that development has been conducted on carbon dioxide adsorbents, for example, activated carbon or the like loaded with an amine compound or potassium carbonate (see Patent Literatures 2 and 3).
Among such carbon dioxide adsorbents, a carbon dioxide adsorbent of which the use is being actively pursued is a porous material with an amine compound loaded on its surface, the amine compound acting as a carbon dioxide capturing material. Here, the amine compound serves to adsorb carbon dioxide (see Patent Literatures 3 to 5). Methods disclosed in these conventional arts include a method of loading an amine compound onto alumina, zeolite, a carbon molecular sieve, an ion-exchange resin, a polymer adsorbent, or the like, and a method of regenerating such a carbon dioxide adsorbent through application of heat. Amine compounds have high affinity for carbon dioxide. Therefore, amine compounds easily adsorb low-concentration carbon dioxide present in a living space. In addition, amine compounds that have adsorbed carbon dioxide easily desorb and release the carbon dioxide when subjected to low-temperature heat no higher than 100° C. That is, amine compounds have a feature that their adsorption capacity can be regenerated. Thus, the use of a material loaded with an amine compound makes it possible to only remove carbon dioxide from air in a living space, and to construct a system suitable for purifying air in a living space with a reduced amount of fresh air supply and with reduced energy consumption. There is another conventional art disclosing an air conditioning system where a carbon dioxide adsorbent is regenerated with use of waste heat from an air-conditioning heat source, so that continuous operation of a carbon dioxide separation apparatus is enabled (see Patent Literature 6).